Liner for crinding mills



Aug. 19, 1969 B. D. LANDES ETA L LINER FOR GRINDING MILLS Filed Dec. 14, 1966 INVENTORS ATTORNE v United States Patent 3,462,090 LINER FOR GRINDING MILLS Benjamin Daniel Landes, Denver, and Ramon Paricio, Jr.,

and Richard E. Andrews, Golden, Colo., assignors to Coors Porcelain Company, Golden, Colo., a corporation of Colorado Filed Dec. 14, 1966, Ser. No. 601,728 Int. Cl. B02c 17/22 US. Cl. 241-299 14 Claims ABSTRACT OF THE DISCLOSURE Liner assembly for cylindrical grinding mill wherein a plurality of liner units are circumferentially disposed; each unit includes two subunits each of which comprises a plurality of ceramic blocks disposed on a retaining sheet having spaced retaining flanges. Between adjacent units is a wedge member wherein is disposed and retained a second plurality of ceramic blocks.

This invention relates to a liner assembly of the type suitable for use in grinding mills.

Although the invention will be described and illustrated in connection with a ball or rod-type grinding mill with which it has particularly advantageous utility, it will be understood that the liner assembly of the instant invention is adaptable for use in machines other than grinding mills and as a wear-resistant, corrosion-resistant lining for ducts, conduits or chutes.

-Ball and rod-type grinding mills utilize a substantially cylindrical shell made of heavy rolled plate steel. Liners are secured to the inside surfaces of the cylindrical shell and rods or balls are loosely disposed within the shell. Crude ores are fed into one end of the cylindrical shell and as the shell rotates the balls or rods, whichever the case may be, pulverize the ore. The pulverized ore moves out the opposite end of the cylindrical shell.

The two most important characteristics of the lining material to be used in such grinding mills is that the lining be corrosion resistant and abrasion resistant. In the past, such liners have been made of ferrous metal alloys and include a plurality of individual sections. Each individual section is secured in place within the cylindrical shell by a bolt which passes through each liner section and through the shell. The shells of many such grinding mills are regularly eight feet or more in diameter and, therefore, require a large number of individual liner sections and a large number of bolts to secure the respective sections in position. One problem associated with the liners made of ferrous metal alloys is that they wear out rapidly, and this in turn requires extensive down time for replacing the liners. A long down time is required because each individual section of the liner must be removed and replaced by removing and reinserting the bolt which secures each individual section in position. In addition, the wear of a metal liner causes metal particles from the liner to be mixed with the material being ground and in many instances it is very diflicult and costly to separate such particles from the ground material.

Ceramic liners have been found very satisfactory in Patented Aug. 19, 1969 that their corrosion and abrasion resistant characteristics provide a longer lasting liner as compared to a liner made of ferrous metal alloys. In addition, the liners made of ferrous metal alloys are much heavier than ceramics and it is, therefore, more expensive and more difficult to rotate a grinding mill shell having a ferrous metal alloy liner than to rotate a grinding mill shell having a ceramic liner.

Heretofore, however, it has been difficult to fabricate a ceramic liner which may be easily and satisfactorily retained in position within the grinding mill shell. Because of the nature of ceramics, it has not proven feasible to mold individual liner sections of ceramic with holes therethrough so that each section can be secured to the shell of the grinding mill by a bolt which extends through the ceramic section and through the shell. Individual ceramic sections have been adhesively secured to grinding mill shells by cement but this has not proven entirely satisfactory since the cement cracks and otherwise deteriorates.

Down time to reline a mill with the subunits of the liner assembly of the instant invention is a minimum time. Where the mills have been lined with ceramic blocks, the down time required to cement the blocks into the mill individually and then water-cure the lining before use has been as much as several days. Alloy steel liners can be assembled faster than the cemented ceramic blocks but are twice the weight of ceramic of the same size and ceramic is much harder.

Accordingly, it is an object and feature of this invention to provide a liner assembly of the type which has particular utility in grinding mills and which includes a plurality of ceramic blocks which may be preassembled and shipped in subunits and installed in a grinding mill shell in a minimum of down time.

Another object and feature of this invention is to provide a liner assembly including a plurality of ceramic blocks and wedge means for forcing the blocks together to prevent relative movement between the blocks so as to retain the blocks in position to form a liner.

In general, these and other objects and features of this invention may be attained in a preferred embodiment including a plurality of liner units which may be disposed circumferentially about the inside of a cylindrical grinding mill. Each of the units includes two subunits and a substantially V-shaped wedge means. Each subunit includes a retaining sheet having spaced flanges and a plurality of ceramic blocks disposed on the retaining sheet and filling the space between the flanges. The retaining sheet maintains the ceramic blocks in position for shipping and for disposition within the grinding mill shell. The wedge means includes a V-shaped wedge member having a base and diverging sides. A plurality of ceramic blocks, which also have diverging sides, are disposed in side-byside relationship in the V-shaped member. There is also included groove and ridge means for retaining the blocks in the V-shaped wedge member. A bolt or the like extends through the base portion of the V-shaped wedge member so that when a plurality of the units are disposed in a grinding mill shell, the bolt extends through the grinding mill shell. The units are disposed in abutting relationship about the circumference of the cylindrical shell and the V-shaped wedge member is disposed between the two subunits of each unit so that upon tightening of the bolts,

the V-shaped wedge member forces the subunits on either side thereof apart and into binding engagement with the subunits of the adjacent unit so that when all the V-Shaped wedge members are thus forced into position by the bolts, the subunits are in binding engagement with one another and thereby held and retained in position within the grinding mill shell.

Other objects and attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIGURE 1 is an elevationalview of a grinding mill of the type with which the instant invention has very satisfactory utility;

FIGURE 2 is an enlarged fragmentary cross-sectional view of a portion of the shell of the grinding mill illustrated in FIGURE 1 and including the liner assembly of the instant invention; and

FIGURE 3 is a fragmentary perspective View of the liner assembly shown in FIGURE 2.

Referring now to the drawing wherein like numerals indicate like or corresponding parts throughout the several views, a ball-type cylindrical grinding mill is generally shown at 10. The grinding mill includes a cylindrical shell generally indicated at 12. As alluded to hereinbefore, the shell 12 has a liner disposed on the internal surfaces thereof and raw ore is fed into the shell and pulverized by balls as the shell is rotated, the pulverized ore being moved out the opposite end of the shell.

A preferred embodiment of the liner assembly of the instant invention is generally shown at 14. The liner assembly 14 includes a plurality of liner units which may be disposed circumferentially about the inside of the cylindrical grinding mill 12. Each of the units includes two subunits, each of which is generally indicated at 16, and wedge means generally indicated at 18 for forcing the subunits together to prevent relative movement therebetween and for retaining the subunits in position to form a liner.

Each subunit 16 includes a retaining means comprising the retaining sheet 20 and a plurality of blocks 22. The retaining sheets 20 are preferably made of metal. Each retaining sheet 20 has a curved base portion which abuts the wall of the mill 12 and a pair of spaced flanges 24 and 26 which extend from the base portion in convergent relationship. The ceramic blocks 22 are disposed on the retaining sheet 20 against the curved base portion thereof so as to fill the space between the flanges 24 and 26. A row of blocks 22' are disposed along and engage the flange 26. The row of blocks 22' of each subunit extends upward from the retaining sheet 20 further than the remainder of the blocks 22 disposed between the flanges 24 and 26.

As alluded to above, the liners utilized in grinding mills must be replaced when they wear out; thus, such liners are manufactured independently of the grinding mill shell and are shipped to the situs of the grinding mill for insertion into the grinding mill in substitution for the worn-out liners. Each subunit 16 of the instant invention may be shipped as an integral package in that the retaining sheet 20 maintains the relative position between the ceramic blocks 22 and 22 and, during such shipment, one or more metal bands may be disposed about the retaining sheet 20 to firmly hold the ceramic blocks 22 and 22 in the position during such shipment. Once a subunit 16 reaches the situs of the grinding mill, the metal bands are removed as the subunit is placed within the shell of the grinding mill.

The first flange 26 of each of the subunits 16 is spaced from a first flange 26 of the adjacent subunit 16 when the subunits are disposed about the cylindrical grinding mill shell 12. Each row of blocks 22 which engage the flange 26 presents an inclined surface so that the first flange 26 of each subunit 16 lies in the plane which intersects the plane of the first flange 26 of the adjacent subunit when the subunits 16 are disposed within a cylindrical grinding mill. That is to say and as best illustrated in FIGURE 2, the plane in which the flange 26 of one subunit is disposed intersects the plane in which the flange 26 of the adjacent subunit is disposed. The second flange 24 of each subunit is disposed in abutting engagement with the second flange 24 of the ad jacent subunit when the subunits are disposed in the cylindrical grinding mill.

The wedge means 18 includes substantially V-shaped wedge members 30 and another plurality of ceramic blocks 32. Each V-shaped member 30 has a base and diverging sides 34. Each of the ceramic blocks 32 has diverging sides and is disposed in a V-shaped wedge member 30 and extends between the diverging sides thereof. There is also included means for retaining the blocks 32 in the V-shaped member 30, such means comprising the grooves 36 in the sides of the blocks 32 and the coacting ridges 38 along the sides 34 of the V-shaped members 30. The ridges 38 are disposed in the grooves 36 to retain the blocks 32 in the V-shaped wedge member 30.

Associated with each V-shaped wedge member 30 is at least one fastening means comprising the bolt 40. When the components are disposed in a grinding mill shell 12, the bolts 40 extend through the base of the V-shaped wedge member 30 and through the grinding mill shell. When in this position, the V-shaped wedge member 30 is disposed in engagement with and between the first flanges 26 of adjacent subunits 16 and the bolt 40 extends through the cylindrical grinding mill shell 12. A rubber-like seal 42 and a washer 44 are disposed on the bolt and held in place by a nut 46. Upon tightening the nut 46, the V-shaped wedge member 30 is forced between adjacent subunits 16 to retain the subunits 16 in position as they are forced into engagement with subunits of adjacent units. It will be noted that the base of the V-shaped wedge member 30 is spaced from the grinding mill shell 12, such space provides a tolerance for pulling the V-shaped wedge member 30 toward the grinding mill shell 12.

The blocks 32 which are disposed in the V-shaped member 30 have a suflicient height to extend beyond the extremities of the sides 34 of the V-shaped wedge member 30 and, in addition, extend beyond the extremities of the rows of blocks 22'. As alluded to previously, the invention is being described as an embodiment suitable for use in grinding mills of the type utilizing balls or rods. When such balls or rods are utilized, they move within the grinding mill shell 12 and fall upon and pulverize the ore as the grinding mill shell rotates. The projections provided by the upward extension of the ceramic blocks 22', and 32 above the blocks 22 provide a means for engaging such rods or balls to move such rods or balls generally radially inwardly as the shell '12 rotates after which the balls or rods move radially outward to impact upon the crude ore disposed over the ceramic blocks 22. In other words, the projections provided by the blocks 22' and 32 force the rods or balls to carry upward with the mill as it rotates and prevents the rods or balls from slipping and remaining at the bottom of the mill.

Where it is not desired to provide the effect of a lifterbar liner as has been illustrated, but to provide a smooth liner, the height dimension of the wedge means 18 is reduced to eliminate its protrusion into the mill beyond the upper extremity of the blocks 22. Thus, the blocks 22' and the blocks 32 are reduced in height so as not to extend higher or radially inwardly more than the blocks 22. It is thereby practical to provide a plain, smooth lining secured in place by a wedge means that seats at the same radial dimension as the main field of blocks.

In addition, in some instances it may be preferable to utilize the adjustment shims 48 between the V-shaped wedge members 30 and the flanges 26.

The ends of the grinding mill shell 12 are also provided with a liner (which is not shown). The distance between such ends may be such that a number of subunits 16 are disposed in end-to-end relationship to cover the entire length of the interior of the shell 12. In such instances, it has been found desirable to dispose a wedging member 30 in overlapping relationship between laterally disposed subunits 16, i.e., engaging four subunits 16, pairs of which are disposed in end-to-end relationship.

The instant invention, therefore, provides a novel liner assembly which is particularly suited for use in grinding mills in that the liner assembly of the instant invention includes a plurality of ceramic blocks, preferably a high alumina ceramic which has high corrosion and abrasion resistance, and which liner assembly may be installed in a grinding mill shell with a minimum of down time. More specifically, each of the subunits 16 may be shipped as a unit in that the metal bands may be disposed about the retaining sheets 20 to hold the blocks 22 and 22' in position until each subunit 16 is disposed within the shell 12. The V-shaped wedge members 30 are disposed between adjacent subunits 16 and are forced into wedging engagement therewith by bolts 40. It is clear, therefore, that a greatly reduced number of bolts is required to hold the instant liner assembly in position within the grinding mill shell 12; that is, as compared to the number of bolts normally utilized to hold the prior art liners in position. Thus, a liner made in accordance with the instant invention lasts longer and may be replaced in less time than the liner assemblies heretofore utilized.

Although the instant invention has been illustrated and described in a preferred embodiment suitable for use in ball or rod type grinding mills, it is to be understood that the liner assembly of the instant invention may be used in various other assemblies to equal advantage. In addition, it will be understood that the surface geometry may be other than cylindrical, such as flat, convex, cubical, etc.

The invention has been described in an illustrative manner and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A liner assembly comprising: a plurality of blocks, and wedge means for maintaining said blocks in position to form a liner, said plurality of blocks being divided into a plurality of subunits each of which includes a number of said blocks, each subunit including retainer means for maintaining the relative position between the blocks thereof.

2. A liner assembly as set forth in claim 1 wherein said retainer means comprises a sheet to which said blocks are secured.

3. A liner assembly as set forth in claim 2 wherein said sheet has a pair of spaced flanges with the blocks substantially filling the space between said flanges.

4. A liner assembly as set forth in claim 1 wherein said wedge means is disposed between adjacent subunits.

5. A liner assembly as set forth in claim 4 wherein said wedge means includes; a divergent member having a base and diverging sides, a second plurality of blocks disposed between said diverging sides, and means for retaining said second plurality of blocks between said diverging sides.

6. A liner assembly as set forth in claim 5 including fastening means for extending through said base of said divergent member so that said diverging sides thereof may be drawn into wedging engagement between adjacent subunits.

7. A liner assembly as set forth in claim 5 wherein said liner assembly includes a plurality of units and each of said units comprises two of said subunits and said wedge means for disposition between the subunits.

8. A liner assembly of the type for use in a cylindrical grinding mill, said liner assembly comprising: a plurality of liner units which may be disposed circumferentially about the inside of a cylindrical grinding mill; each of said units including two subunits each of which comprises a retaining sheet having a pair of spaced flanges, a first plurality of ceramic blocks disposed on said retaining sheet and filling the space between said flanges, a row of said blocks disposed along and engaging a first of said flanges, said first flange of each of said subunits being spaced from a first flange of another subunit when disposed about said cylindrical grinding mill, said row of blocks engaging said first flange in each of said subunits presenting a surface so that said first flange of one subunit lies in a plane which intersects the plane of the first flange of the adjacent subunit when said subunits are disposed within said cylindrical grinding mill, the second flange of each subunit being disposed in abutting engagement with the second flange of another subunit when disposed in said cylindrical grinding mill; each of said units further including a substantially V-shaped wedge member, a second plurality of ceramic blocks having diverg ing sides and disposed in said V-shaped wedge member, each of said second plurality of blocks having a groove in each side thereof and said V-shaped wedge member having a ridge extending therealong on each side thereof for disposal in said grooves to retain said second plurality of blocks in said V-shaped wedge member, and at least one aperture in said V-shaped wedge member so that a fastening means may extend through said V-shaped wedge member whereby said V-shaped wedge member may be disposed in engagement with and between first flanges of adjacent subunits with the fastening means extending through the cylindrical grinding mill so that said V-shaped wedge member may be forced between adiacent subunits to retain the latter in position as the subunits of one unit are forced into engagement with the subunits of adjacent units.

9. A liner assembly as set forth in claim 8 wherein the blocks which engage the first flange in each subunit extend upward from said retaining sheet further than the remainder of said blocks which are disposed between the flanges thereof, said second plurality of blocks having suflicient height to extend beyond the extremities of said sides of said V-shaped wedge member and to extend beyond the extremities of said blocks which engage said first flanges in the adjacent subunits.

10. A liner assembly as set forth in claim 9 wherein said V-shaped wedge member is disposed in spaced relationship to the cylindrical grinding mill when said liner assembly is disposed therein.

11. A subunit for a liner assembly of the type used in a grinding mill, said subunit comprising; a plurality of ceramic blocks, and a retainer sheet having a curved base portion and a pair of flanges which extend from said base portion in convergent relationship, said blocks being disposed along said base portion between and substantially filling the space between said flanges.

12. A subunit of the type set forth in claim 11 wherein one of said flanges and the blocks adjacent thereto extend further from said sheet than the other flange and the remainder of the blocks.

13. A wedge subassembly for a liner assembly of the type used in a grinding mill, comprising: a divergent member having a base and a pair of diverging sides extending therefrom, a plurality of blocks in said divergent member, each of said blocks extending between said diverging sides, and means for retaining said blocks between said diverging sides.

14. A wedge subassembly as set forth in claim 13 wherein said blocks extend beyond the extremities of said divergent sides of said divergent member.

References Cited UNITED STATES PATENTS 'Drader 51-204 Posselt 241-183 Rosenqvist 241-183 landes 241-183 X Smith 241-294 LESTER M. SWINGLE, Primary Examiner D. G. KELLY, Assistant Examiner 

